See, it's the reverse for me because 6 months of training isn't nearly enough time to get to a superior level against people that have been established at that level or beyond for x amount of time. These guys, every single one listed, is fighting at or beyond Captain level from the start or Elf saga, which is tremendous considering. Hell, they surpassed the Spirit Guardians (Except Gaja) and they were the ones teaching them lol.
Luck is Luck, from the start he's been known for 2 things: Speed and his genius intellect/Mana sense. He found a way to push his Speed through the roof, so it's a net win for a side character.
Charmy took next to no damage and wrecked that Disciple, while showcasing a completely new ability. Add to that they established that she's a Dwarf, which is completely unexplored and I guess it explains her seemingly limitless powerups.
Leo is in a fukked up spot because he's never EVER going to surpass either of his siblings. shyt just ain't happening. So everything he does is going to come off weak. His special ability is to absorb ass whippings until he can find a solution. He got a W, which he's never gotten before. Progress, I guess.
Mimosa... well she did kill the nikka originally but was back to trash bag status once he was revived. She pulled off a draw, that's some amazing shyt considering she's a support character, at best.
Noelle improved the most outside Asta. Even with her power cut in half, she went to the limit with Vanica at 70%. She was
NEVER going to win that after a training montage of 6 months. Pre time skip, she would have been food like Mimosa.
All four of them nikkas are garbage juice.
Vanessa has a dynamic game changing ability but that's all she exists as: a Uno Reverse card. They keep hinting at Grey having some unknown ability but I don't know if she can be salvaged.